I have an interrupt component connected to the SS pin of SPI. It is configured as rising edge. Each time the SS pin is released from low to high, the ISR should trigger.
The problem is that the ISR is triggering multiple times at a very high speed. Successive after 6us delay. The SS pin only gives a rising edge once in 1ms.
Even if I connect the ISR to the interrupt pin of the SPI block instead of the SS pin, the same problem occurs. When I connect it to the SPI external interrupt pin I change the ISR type to level triggered and take care to call the clear_pending() function.
The SPI pins are all on port-4 which is a non-DSI port.
The problem is solved...
The slave SPI was powered by a 3.3V source while the master by a 5V source. I changed the voltage regulator on the slave to 5V and now everything is OK